CN104253654A - Device and method for improving modulation performance of MZ (Mach Zehnder) modulator - Google Patents

Abstract

The invention discloses a device and a method for improving modulation performance of an MZ (Mach Zehnder) modulator, and relates to optical fiber communication, in particular to the field of coherent light communication. The device comprises a laser, an arcsin function transformation unit, a digital-analog conversion (DAC) unit and an MZM unit. The arcsin function transformation unit is used for performing arcsin function preprocessing on input digital signals of the MZ modulator to enable the preprocessed signals to work in an MZM (Mach Zehnder modulator) non-linear area without distortion. The DAC unit converts digital electric signals processed by the arcsin function transformation unit into analog electric signals. The MZM unit modulates optical carrier waves output by the laser by means of the analog electric signals converted by the DAC unit. According to the technical scheme, through Arcsin (arcsin function) preprocessing of the digital signals, non-linear influences of MZ field modulation are effectively restrained, and output luminous power of a transmitter is improved.

Description

A kind of apparatus and method improving MZ modulators modulate performance

Technical field

The present invention relates to optical fiber communication particularly coherent optical communication field, be specifically related to the preliminary treatment of originating terminal signal and the modulation scheme of MZM.

Background technology

Based on the coherent optical communication system of higher order modulation formats, adapt to the development of current optical-fiber network, constructed the optical transport network demand of two-forty, high power capacity, low cost.Coherent optical communication system extensive use MZM based on higher order modulation formats carries out optical sender I/Q modulation.MZM is a nonlinear modulator, and when drive singal amplitude is very little, due to the impact of extinction ratio, MZM cannot realize linear field modulation.When increase signal amplitude with eliminate extinction ratio undesirable cause affect time, if signal amplitude exceeds MZM linear field modulating range, signal can introduce irreversible distortion equally, causes the deterioration of error rate of system performance.

Based in the coherent optical communication system of higher order modulation formats, for the signal that papr is larger, the amplitude excursion of signal is very large.When using MZM to carry out linear field modulation to high PAPR signal, in order to avoid undesirable extinction ratio causes modulating performance to worsen, drive singal can not control too little.Because signal has higher PAPR, the drive singal therefore inevitably having some peak values drops in nonlinear area, can cause the nonlinear distortion of modulation signal.Therefore, how to overcome PAPR and a problem demanding prompt solution is just become on the impact of MZM.

Summary of the invention

Technical problem to be solved by this invention is, provides a kind of apparatus and method improving MZ (Mach-Zehnder, Mach-Zehnder) modulators modulate performance, with the impact of the on-the-spot Modulation and Nonlinear of the MZ that degrades.

In order to solve the problems of the technologies described above, the invention discloses a kind of device improving MZ modulators modulate performance, comprise laser, this device also comprises:

Arcsin function converter unit, carries out arcsin function preliminary treatment to the supplied with digital signal of MZ modulator, makes pretreated signal be operated in MZM nonlinear area and undistorted;

Analog-to-digital conversion (DAC) unit, is converted to analog electrical signal by the digital electric signal after the process of described arcsin function conversion module;

MZM unit, utilizes the analog electrical signal of described DAC cell translation to modulate the light carrier of described laser output.

Preferably, in said apparatus, the described supplied with digital signal to MZ modulator carries out arcsin function preliminary treatment and refers to:

Described arcsin function converter unit, according to the signal response characteristic of MZM, carries out corresponding inverse transformation to input signal.

Preferably, in said apparatus, described arcsin function converter unit carries out arcsin function preliminary treatment according to following formula to supplied with digital signal:

${s_n}^{\′}=\left\{\begin{array}{c}\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\·\arcsin (\mathrm{\η}\·s_n),|\mathrm{\η}\·s_n|\≤1\\ \frac{s_n}{\left|s_n\right|}\·\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\·\arcsin \left(1\right),|\mathrm{\η}\·s_n|>1\end{array}\right.$

In above formula, s _nfor supplied with digital signal, V _pifor the half-wave voltage of MZM, η is the coefficient of control MZM drive singal size, s _n' be through the pretreated output digit signals of arcsin function.

Preferably, in said apparatus, described arcsin function converter unit comprises one or more arcsin function conversion module.

Preferably, in said apparatus, when described arcsin function converter unit comprises multiple arcsin function conversion module, described analog-to-digital conversion (DAC) unit comprises and the as many DAC of arcsin function conversion module quantity, and described MZM unit comprises and the as many MZM of arcsin function conversion module quantity.

Preferably, in said apparatus, when described arcsin function converter unit comprises two arcsin function conversion modules, supplied with digital signal is divided into I road and Q road, two arcsin function conversion modules carry out arcsin function preliminary treatment to the supplied with digital signal on I road and Q road respectively, then the digital electric signal after process is sent to MZM process corresponding in DAC and MZM unit corresponding in analog-to-digital conversion (DAC) unit respectively.

Preferably, in said apparatus, when described arcsin function converter unit comprises two arcsin function conversion modules, two arcsin function conversion modules carry out arcsin function preliminary treatment according to the supplied with digital signal of following formula to I road and Q road respectively:

$\mathrm{Re}{\left\{s_n\right\}}^{\′}=\left\{\begin{array}{c}\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin (\mathrm{\η}\·\mathrm{Re}\{s_n\left\}\right),|\mathrm{\η}\·\mathrm{Re}\{s_n\left\}\right|\≤1\\ \frac{\mathrm{Re}\left\{s_n\right\}}{\left|\mathrm{Re}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin \left(1\right)=\frac{\mathrm{Re}\left\{s_n\right\}}{\left|\mathrm{Re}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{2},|\mathrm{\η}\·\mathrm{Re}\{s_n\left\}\right|>1\end{array}\right.$

$\mathrm{Im}{\left\{s_n\right\}}^{\′}=\left\{\begin{array}{c}\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin (\mathrm{\η}\·\mathrm{Im}\{s_n\left\}\right),|\mathrm{\η}\·\mathrm{Im}\{s_n\left\}\right|\≤1\\ \frac{\mathrm{Im}\left\{s_n\right\}}{\left|\mathrm{Im}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin \left(1\right)=\frac{\mathrm{Im}\left\{s_n\right\}}{\left|\mathrm{Im}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{2},|\mathrm{\η}\·\mathrm{Im}\{s_n\left\}\right|>1\end{array}\right.$

In above formula, Re{s _n, Im{s _nbe respectively the supplied with digital signal on I road and Q road in I/Q modulated process, V _pifor the half-wave voltage of MZM, η is the coefficient of control MZM drive singal size, Re{s _n' and Im{s _n} ' be respectively I road and Q road are through the pretreated output digit signals of arcsin function.

The invention also discloses a kind of method improving MZ modulators modulate performance, comprising:

Arcsin function preliminary treatment is carried out to the supplied with digital signal of MZ modulator, makes pretreated signal be operated in MZM nonlinear area and undistorted, more pretreated for arcsin function digital electric signal is converted to analog electrical signal;

Utilize the light carrier that the analog electrical signal modulated laser after conversion exports.

Preferably, in said method, arcsin function preliminary treatment is carried out to the supplied with digital signal of MZ modulator and refers to:

According to the signal response characteristic of MZM, corresponding inverse transformation is carried out to input signal.

Preferably, in said method, according to following formula, arcsin function preliminary treatment is carried out to supplied with digital signal:

${s_n}^{\′}=\left\{\begin{array}{c}\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\·\arcsin (\mathrm{\η}\·s_n),|\mathrm{\η}\·s_n|\≤1\\ \frac{s_n}{\left|s_n\right|}\·\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\·\arcsin \left(1\right),|\mathrm{\η}\·s_n|>1\end{array}\right.$

In above formula, s _nfor supplied with digital signal, V _pifor the half-wave voltage of MZM, η is the coefficient of control MZM drive singal size, s _n' be through the pretreated output digit signals of arcsin function.

Preferably, said method also comprises:

One or multiple signals are divided into process the supplied with digital signal of MZ modulator.

Preferably, in said method, when being divided into two paths of signals to process the supplied with digital signal of MZ modulator, supplied with digital signal is divided into I road and Q road, respectively arcsin function preliminary treatment is carried out to the supplied with digital signal on I road and Q road, again the digital electric signal after process is converted to analog signal respectively, utilizes the light carrier that the two-way analog electrical signal modulated laser after conversion exports.

Preferably, in said method, when being divided into two paths of signals to process the supplied with digital signal of MZ modulator, carry out arcsin function preliminary treatment according to the supplied with digital signal of following formula to I road and Q road respectively:

$\mathrm{Re}{\left\{s_n\right\}}^{\′}=\left\{\begin{array}{c}\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin (\mathrm{\η}\·\mathrm{Re}\{s_n\left\}\right),|\mathrm{\η}\·\mathrm{Re}\{s_n\left\}\right|\≤1\\ \frac{\mathrm{Re}\left\{s_n\right\}}{\left|\mathrm{Re}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin \left(1\right)=\frac{\mathrm{Re}\left\{s_n\right\}}{\left|\mathrm{Re}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{2},|\mathrm{\η}\·\mathrm{Re}\{s_n\left\}\right|>1\end{array}\right.$

$\mathrm{Im}{\left\{s_n\right\}}^{\′}=\left\{\begin{array}{c}\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin (\mathrm{\η}\·\mathrm{Im}\{s_n\left\}\right),|\mathrm{\η}\·\mathrm{Im}\{s_n\left\}\right|\≤1\\ \frac{\mathrm{Im}\left\{s_n\right\}}{\left|\mathrm{Im}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin \left(1\right)=\frac{\mathrm{Im}\left\{s_n\right\}}{\left|\mathrm{Im}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{2},|\mathrm{\η}\·\mathrm{Im}\{s_n\left\}\right|>1\end{array}\right.$

In above formula, Re{s _n, Im{s _nbe respectively the supplied with digital signal on I road and Q road in I/Q modulated process, V _pifor the half-wave voltage of MZM, η is the coefficient of control MZM drive singal size, Re{s _n' and Im{s _n} ' be respectively I road and Q road are through the pretreated output digit signals of arcsin function.

Technical scheme by carrying out Arcsin (arcsin function) preliminary treatment to digital signal, thus suppresses the impact of the on-the-spot Modulation and Nonlinear of MZ effectively, improves transmitter Output optical power.

Embodiment

Fig. 1 is the apparatus structure schematic diagram improving MZM field modulating performance in the application's preferred embodiment;

Fig. 2 is that Fig. 1 shown device improves 16QAM-CO-OFDM transmission system MZM field modulating performance schematic diagram;

Fig. 3 is the function table trrellis diagram that Fig. 1 shown device realizes numeric field Arcsin converter unit;

Fig. 4 is the method flow diagram that the application's preferred embodiment improves MZM field modulating performance.

Embodiment

For making the object, technical solutions and advantages of the present invention clearly understand, hereafter will be described in further detail technical solution of the present invention by reference to the accompanying drawings.It should be noted that, when not conflicting, the feature in the embodiment of the application and embodiment can combine arbitrarily mutually.

Embodiment 1

The present embodiment provides a kind of device improving MZM modulating performance, and device comprises laser, Arcsin converter unit, DAC unit and MZM unit, introduces the operation principle of each several part below.

Laser, provides light carrier;

Arcsin conversion module unit, in order to the Arcsin preliminary treatment of the digital signal of the input to MZ modulator, pretreated signal can be operated in MZM nonlinear area and undistorted.

Wherein, its Arcsin computational methods of above-mentioned Arcsin conversion module comprise look-up table, but are not limited only to look-up table.

And above-mentioned Arcsin conversion module unit carries out arcsin function preliminary treatment to the supplied with digital signal of MZ modulator refers to: Arcsin converter unit, according to the signal response characteristic of MZM, carries out corresponding inverse transformation to input signal.

In the present embodiment, Arcsin conversion module can carry out Arcsin preliminary treatment according to the digital signal of following formula to input:

${s_n}^{\′}=\left\{\begin{array}{c}\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\·\arcsin (\mathrm{\η}\·s_n),|\mathrm{\η}\·s_n|\≤1\\ \frac{s_n}{\left|s_n\right|}\·\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\·\arcsin \left(1\right),|\mathrm{\η}\·s_n|>1\end{array}\right.$

In above formula, s _nfor supplied with digital signal, V _pifor the half-wave voltage of MZM, η is the coefficient of control MZM drive singal size, s _n' be through the pretreated output digit signals of Arcsin.

After modulating according to above-mentioned formula, input signal is linear with output signal, and can not cause distortion by nonlinear impact of MZM.

The data of above-mentioned Arcsin converter unit input need carry out value in [-1,1] scope.

In addition, this

DAC unit, for being converted to analog electrical signal by number digital electric signal after the process of Arcsin conversion module.

MZM unit, for the described light carrier utilizing the analog electrical signal of DAC cell translation to modulate the output of described laser, carries out electrical/optical conversion.

Embodiment 2

The present embodiment provides a kind of method improving MZ modulators modulate performance, responsible but be not limited to above-described embodiment 1 device realize, the method operates as follows:

Arcsin preliminary treatment is carried out to the supplied with digital signal of MZ modulator, makes pretreated signal be operated in MZM nonlinear area and undistorted, more pretreated for Arcsin digital electric signal is converted to analog electrical signal;

Utilize the light carrier that the analog electrical signal modulated laser after conversion exports.

Wherein, carrying out Arcsin preliminary treatment to the supplied with digital signal of MZ modulator is: according to the signal response characteristic of MZM, carry out corresponding inverse transformation to input signal.

In the present embodiment, Arcsin preliminary treatment can be carried out according to following formula to supplied with digital signal:

${s_n}^{\′}=\left\{\begin{array}{c}\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\·\arcsin (\mathrm{\η}\·s_n),|\mathrm{\η}\·s_n|\≤1\\ \frac{s_n}{\left|s_n\right|}\·\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\·\arcsin \left(1\right),|\mathrm{\η}\·s_n|>1\end{array}\right.$

In above formula, s _nfor supplied with digital signal, V _pifor the half-wave voltage of MZM, η is the coefficient of control MZM drive singal size, s _n' be through the pretreated output digit signals of Arcsin.

It should be noted that, in actual applications, can one or multiple signals are divided into process the supplied with digital signal of MZ modulator.

Embodiment 3

The present embodiment provides a kind of device of preferred improvement MZM modulating performance, and it is mainly optimized on the basis of above-described embodiment 1.It is mainly for the modulation system of 16QAM, input signal is proposed to be divided into I road and Q road two paths of signals to process, now, Arcsin conversion module unit in the device of MZM modulating performance can comprise two Arcsin conversion modules, DAC unit comprises two DAC, MZM unit and comprises two MZM, and its structure as shown in Figure 1.These two Arcsin conversion modules carry out Arcsin preliminary treatment to the I road of input signal and the supplied with digital signal on Q road respectively, specifically can calculate according to following formula.

$\mathrm{Re}{\left\{s_n\right\}}^{\′}=\left\{\begin{array}{c}\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin (\mathrm{\η}\·\mathrm{Re}\{s_n\left\}\right),|\mathrm{\η}\·\mathrm{Re}\{s_n\left\}\right|\≤1\\ \frac{\mathrm{Re}\left\{s_n\right\}}{\left|\mathrm{Re}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin \left(1\right)=\frac{\mathrm{Re}\left\{s_n\right\}}{\left|\mathrm{Re}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{2},|\mathrm{\η}\·\mathrm{Re}\{s_n\left\}\right|>1\end{array}\right.$

$\mathrm{Im}{\left\{s_n\right\}}^{\′}=\left\{\begin{array}{c}\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin (\mathrm{\η}\·\mathrm{Im}\{s_n\left\}\right),|\mathrm{\η}\·\mathrm{Im}\{s_n\left\}\right|\≤1\\ \frac{\mathrm{Im}\left\{s_n\right\}}{\left|\mathrm{Im}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin \left(1\right)=\frac{\mathrm{Im}\left\{s_n\right\}}{\left|\mathrm{Im}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{2},|\mathrm{\η}\·\mathrm{Im}\{s_n\left\}\right|>1\end{array}\right.$ In above formula, Re{s _n, Im{s _nbe respectively the supplied with digital signal on I road and Q road in I/Q modulated process, V _pifor the half-wave voltage of MZM, η is the coefficient of control MZM drive singal size, Re{s _n' and Im{s _n} ' be respectively I road and Q road are through the pretreated output digit signals of Arcsin.

It is emphasized that the scene that device that the present embodiment proposes is not limited in 16QAM-OFDM input signal uses.According to different scenes, can suitably adjust.

Below in conjunction with Fig. 2, illustrate this preferred embodiment how to improve 16QAM-CO-OFDM system MZM field modulating performance by Arcsin conversion module., the device of preferred MZM modulating performance comprises laser, 18,16-QAM constellation mapping unit 10, string is change unit 11, IFFT unit 12 also, and string location 13, real part Arcsin unit 14 and imaginary part Arcsin unit 15, DAC unit 16,17, MZM unit 19,20, and pi/2 phase shifter 21.Wherein, real part Arcsin unit 14 and imaginary part Arcsin unit 15 realize by look-up table, as shown in Figure 3.

Embodiment 4

The present embodiment provides a kind of method improving 16QAM-CO-OFDM system MZM light modulation performance based on Arcsin conversion, and the realization of the method can be dependent on the device realization of embodiment 3, and specific implementation comprises the steps 400 to 406:

Step 400, binary system bit flows to into 16QAM constellation mapping unit 10, produces 16QAM symbol S _n.

Step 401,16QAM symbol S _nmultidiameter delay data are formed through serial to parallel conversion unit 11.

Step 402, multidiameter delay data form ofdm signal through IFFT unit 12.

Step 403, parallel ofdm signal data form serial data through parallel serial conversion unit 13.

Step 404, the ofdm signal S that serial to parallel conversion unit 13 exports _nask its real part and imaginary part respectively, input real part Arcsin unit 14 and imaginary part Arcsin unit 15, change as follows.

$\mathrm{Re}{\left\{s_n\right\}}^{\′}=\left\{\begin{array}{c}\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin (\mathrm{\η}\·\mathrm{Re}\{s_n\left\}\right),|\mathrm{\η}\·\mathrm{Re}\{s_n\left\}\right|\≤1\\ \frac{\mathrm{Re}\left\{s_n\right\}}{\left|\mathrm{Re}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin \left(1\right)=\frac{\mathrm{Re}\left\{s_n\right\}}{\left|\mathrm{Re}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{2},|\mathrm{\η}\·\mathrm{Re}\{s_n\left\}\right|>1\end{array}\right.$

$\mathrm{Im}{\left\{s_n\right\}}^{\′}=\left\{\begin{array}{c}\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin (\mathrm{\η}\·\mathrm{Im}\{s_n\left\}\right),|\mathrm{\η}\·\mathrm{Im}\{s_n\left\}\right|\≤1\\ \frac{\mathrm{Im}\left\{s_n\right\}}{\left|\mathrm{Im}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin \left(1\right)=\frac{\mathrm{Im}\left\{s_n\right\}}{\left|\mathrm{Im}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{2},|\mathrm{\η}\·\mathrm{Im}\{s_n\left\}\right|>1\end{array}\right.$

Step 405, the digital signal that real part Arcsin converter unit 14 and imaginary part Arcsin converter unit 15 export carries out analog-to-digital conversion respectively through DAC unit 16,17.

Step 406, the data that DAC unit 16,17 exports are input to MZM unit 19,20, the light carrier that modulated laser produces.

This system schema is crucial, and the Arcsin conversion of numeric field, specifically can use look-up table:

Look-up table can be utilized to carry out in numeric field Arcsin conversion, first Arcsin operation table in look-up table is set, according to the optional not isotopic number of required precision, here for N position Arcsin operation table, what Fig. 3 provided is that Arcsin arithmetic element difference inputs operation result corresponding to data.

Real part Arcsin unit 14 and imaginary part Arcsin unit 15 signal are entered MZM unit 19,20 as drive singal after DAC unit 16,17 is changed, and now the output signal of MZM unit 19,20 is,

$E_{\mathrm{out}}=E_{\mathrm{in}}\·\sin (\frac{\mathrm{\π}}{V_{\mathrm{pi}}}\·\mathrm{Re}{\left\{s\left(t\right)\right\}}^{\′})=E_{\mathrm{in}}\·\mathrm{\η}\·\mathrm{Re}\left\{s_n\right\}$

$E_{\mathrm{out}}=E_{\mathrm{in}}\·\sin (\frac{\mathrm{\π}}{V_{\mathrm{pi}}}\·\mathrm{Im}{\left\{s\left(t\right)\right\}}^{\′})=E_{\mathrm{in}}\·\mathrm{\η}\·\mathrm{Im}\left\{s_n\right\}$

It can thus be appreciated that the method for Arcsin conversion can make MZM meet the requirement of linear field modulation under 16QAM-CO-OFDM system height PAPR.

As can be seen from above-described embodiment, technical scheme used Arcsin transform operation unit to carry out preliminary treatment to signal before the DAC that makes a start, make transmission signal can be operated in Modulation and Nonlinear region, MZM field, avoid the MZM error rate of system that Modulation and Nonlinear district on the scene causes that works to worsen, and improve the service efficiency of system to transmitter laser power.

The all or part of step that one of ordinary skill in the art will appreciate that in said method is carried out instruction related hardware by program and is completed, and described program can be stored in computer-readable recording medium, as read-only memory, disk or CD etc.Alternatively, all or part of step of above-described embodiment also can use one or more integrated circuit to realize.Correspondingly, each module/unit in above-described embodiment can adopt the form of hardware to realize, and the form of software function module also can be adopted to realize.The application is not restricted to the combination of the hardware and software of any particular form.

The above, be only preferred embodiments of the present invention, be not intended to limit protection scope of the present invention.Within the spirit and principles in the present invention all, any amendment made, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (13)

1. improve a device for MZ modulators modulate performance, comprise laser, it is characterized in that, this device also comprises:

Arcsin function converter unit, carries out arcsin function preliminary treatment to the supplied with digital signal of MZ modulator, makes pretreated signal be operated in MZM nonlinear area and undistorted;

Analog-to-digital conversion (DAC) unit, is converted to analog electrical signal by the digital electric signal after the process of described arcsin function conversion module;

MZM unit, utilizes the analog electrical signal of described DAC cell translation to modulate the light carrier of described laser output.

2. device as claimed in claim 1, it is characterized in that, the described supplied with digital signal to MZ modulator carries out arcsin function preliminary treatment and refers to:

Described arcsin function converter unit, according to the signal response characteristic of MZM, carries out corresponding inverse transformation to input signal.

3. device as claimed in claim 2, it is characterized in that, described arcsin function converter unit carries out arcsin function preliminary treatment according to following formula to supplied with digital signal:

${s_n}^{\′}=\left\{\begin{array}{c}\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\·\arcsin (\mathrm{\η}\·s_n),|\mathrm{\η}\·s_n|\≤1\\ \frac{s_n}{\left|s_n\right|}\·\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\·\arcsin \left(1\right),|\mathrm{\η}\·s_n|>1\end{array}\right.$

In above formula, s _nfor supplied with digital signal, V _pifor the half-wave voltage of MZM, η is the coefficient of control MZM drive singal size, s _n' be through the pretreated output digit signals of arcsin function.

4. the device as described in any one of claims 1 to 3, is characterized in that, described arcsin function converter unit comprises one or more arcsin function conversion module.

5. device as claimed in claim 4, it is characterized in that, when described arcsin function converter unit comprises multiple arcsin function conversion module, described analog-to-digital conversion (DAC) unit comprises and the as many DAC of arcsin function conversion module quantity, and described MZM unit comprises and the as many MZM of arcsin function conversion module quantity.

6. device as claimed in claim 5, it is characterized in that, when described arcsin function converter unit comprises two arcsin function conversion modules, supplied with digital signal is divided into I road and Q road, two arcsin function conversion modules carry out arcsin function preliminary treatment to the supplied with digital signal on I road and Q road respectively, then the digital electric signal after process is sent to MZM process corresponding in DAC and MZM unit corresponding in analog-to-digital conversion (DAC) unit respectively.

7. device as claimed in claim 6, it is characterized in that, when described arcsin function converter unit comprises two arcsin function conversion modules, two arcsin function conversion modules carry out arcsin function preliminary treatment according to the supplied with digital signal of following formula to I road and Q road respectively:

$\mathrm{Re}{\left\{s_n\right\}}^{\′}=\left\{\begin{array}{c}\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin (\mathrm{\η}\·\mathrm{Re}\{s_n\left\}\right),|\mathrm{\η}\·\mathrm{Re}\{s_n\left\}\right|\≤1\\ \frac{\mathrm{Re}\left\{s_n\right\}}{\left|\mathrm{Re}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin \left(1\right)=\frac{\mathrm{Re}\left\{s_n\right\}}{\left|\mathrm{Re}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{2},|\mathrm{\η}\·\mathrm{Re}\{s_n\left\}\right|>1\end{array}\right.$

$\mathrm{Im}{\left\{s_n\right\}}^{\′}=\left\{\begin{array}{c}\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin (\mathrm{\η}\·\mathrm{Im}\{s_n\left\}\right),|\mathrm{\η}\·\mathrm{Im}\{s_n\left\}\right|\≤1\\ \frac{\mathrm{Im}\left\{s_n\right\}}{\left|\mathrm{Im}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin \left(1\right)=\frac{\mathrm{Im}\left\{s_n\right\}}{\left|\mathrm{Im}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{2},|\mathrm{\η}\·\mathrm{Im}\{s_n\left\}\right|>1\end{array}\right.$

In above formula, Re{s _n, Im{s _nbe respectively the supplied with digital signal on I road and Q road in I/Q modulated process, V _pifor the half-wave voltage of MZM, η is the coefficient of control MZM drive singal size, Re{s _n' and Im{s _n} ' be respectively I road and Q road are through the pretreated output digit signals of arcsin function.

8. improve a method for MZ modulators modulate performance, it is characterized in that, comprising:

Arcsin function preliminary treatment is carried out to the supplied with digital signal of MZ modulator, makes pretreated signal be operated in MZM nonlinear area and undistorted, more pretreated for arcsin function digital electric signal is converted to analog electrical signal;

Utilize the light carrier that the analog electrical signal modulated laser after conversion exports.

9. method as claimed in claim 8, is characterized in that, carry out arcsin function preliminary treatment refer to the supplied with digital signal of MZ modulator:

According to the signal response characteristic of MZM, corresponding inverse transformation is carried out to input signal.

10. method as claimed in claim 9, is characterized in that, carry out arcsin function preliminary treatment according to following formula to supplied with digital signal:

${s_n}^{\′}=\left\{\begin{array}{c}\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\·\arcsin (\mathrm{\η}\·s_n),|\mathrm{\η}\·s_n|\≤1\\ \frac{s_n}{\left|s_n\right|}\·\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\·\arcsin \left(1\right),|\mathrm{\η}\·s_n|>1\end{array}\right.$

In above formula, s _nfor supplied with digital signal, V _pifor the half-wave voltage of MZM, η is the coefficient of control MZM drive singal size, s _n' be through the pretreated output digit signals of arcsin function.

11. methods as described in any one of claim 8 to 10, it is characterized in that, the method also comprises:

One or multiple signals are divided into process the supplied with digital signal of MZ modulator.

12. methods as claimed in claim 11, it is characterized in that, when being divided into two paths of signals to process the supplied with digital signal of MZ modulator, supplied with digital signal is divided into I road and Q road, respectively arcsin function preliminary treatment is carried out to the supplied with digital signal on I road and Q road, again the digital electric signal after process is converted to analog signal respectively, utilizes the light carrier that the two-way analog electrical signal modulated laser after conversion exports.

13. methods as claimed in claim 12, is characterized in that, when being divided into two paths of signals to process the supplied with digital signal of MZ modulator, carry out arcsin function preliminary treatment respectively according to the supplied with digital signal of following formula to I road and Q road:

$\mathrm{Re}{\left\{s_n\right\}}^{\′}=\left\{\begin{array}{c}\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin (\mathrm{\η}\·\mathrm{Re}\{s_n\left\}\right),|\mathrm{\η}\·\mathrm{Re}\{s_n\left\}\right|\≤1\\ \frac{\mathrm{Re}\left\{s_n\right\}}{\left|\mathrm{Re}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin \left(1\right)=\frac{\mathrm{Re}\left\{s_n\right\}}{\left|\mathrm{Re}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{2},|\mathrm{\η}\·\mathrm{Re}\{s_n\left\}\right|>1\end{array}\right.$

$\mathrm{Im}{\left\{s_n\right\}}^{\′}=\left\{\begin{array}{c}\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin (\mathrm{\η}\·\mathrm{Im}\{s_n\left\}\right),|\mathrm{\η}\·\mathrm{Im}\{s_n\left\}\right|\≤1\\ \frac{\mathrm{Im}\left\{s_n\right\}}{\left|\mathrm{Im}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{\mathrm{\π}}\arcsin \left(1\right)=\frac{\mathrm{Im}\left\{s_n\right\}}{\left|\mathrm{Im}\right\{s_n\left\}\right|}\·\frac{V_{\mathrm{pi}}}{2},|\mathrm{\η}\·\mathrm{Im}\{s_n\left\}\right|>1\end{array}\right.$

In above formula, Re{s _n, Im{s _nbe respectively the supplied with digital signal on I road and Q road in I/Q modulated process, V _pifor the half-wave voltage of MZM, η is the coefficient of control MZM drive singal size, Re{s _n' and Im{s _n} ' be respectively I road and Q road are through the pretreated output digit signals of arcsin function.